The demand for increase in the precision of light emitting devices has increased as the applications for such devices have become increasingly sophisticated over time. Precision light emitting devices are often employed as point light sources in surgical environments to precisely locate the position of medical instruments in surgical navigation applications. Many manufacturing facilities also employ precision point light sources to derive position data with respect to the relative position of manufacturing tools. The military often use precision light emitting devices to update guidance and navigational data pertaining, for example, missile systems.
Camras et al., U.S. patent application No. 2002/0030194 A1 discloses a light emitting device including a transparent housing having a solid generally hemispherical shape. The light source is bonded to center point of the circle defined by the substantially flat surface of the transparent housing.
Hendrik, U.S. patent application No. 2002/0167485 discloses an image display generator for use in a heads-up display. An array of LEDs are formed on a semiconductor layer deposited on a surface, such as for example, glass. A sapphire sheet with a plurality of lens each having a solid hemispherical shape is disposed on the opposite surface of the glass. The sapphire sheet is aligned so that each LED is aligned with a corresponding sapphire lens.
Hsiong et al., U.S. Pat. No. 5,366,178 discloses the use of an transparent truncated solid hemispherical dome as a protective window for an infrared sensor.